Ghost band (was Re: How to get a single stranded DNA as long as 2-3kb?)

peter via methods%40net.bio.net (by peter.ianakiev from gmail.com)
Tue Jun 12 22:04:09 EST 2007


On Jun 12, 5:31 pm, "Jose de las Heras" <jose... from tiscali.co.uk> wrote:
> "peter" <peter.ianak... from gmail.com> wrote in message
>
> news:1181593924.822581.168770 from q75g2000hsh.googlegroups.com...
>
>
>
> > On Jun 11, 4:22 pm, Nick Theodorakis <nick_theodora... from hotmail.com>
> > wrote:
> >> ChenHA wrote:
>
> >> [...]
>
> >> > Perhaps I misremember, was it XL1 blue cells that produces the ghost
> >> > band of ssDNA instead?
>
> >> I seem to remember a discussion about NaOH irreversibly altering the
> >> plasmid conformation to generate a ghost band during alkaline preps, but
> >> perhaps there is more than one kind of ghost band.
>
> >> Nick
>
> >> --
> >> Nick Theodorakis
> >> nick_theodora... from hotmail.com
> >> contact form:http://theodorakis.net/contact.html
>
> > Guys keep it focussed ... the original poster asked a specific
> > question - 2-3 kb ssDNA out of a plasmid with 3 kb insert. There is no
> > such thing like "ghost" bands. If the culture is overgrown the plasmid
> > does not have time to separate and you have occasionally  concatenates
> > -  thats all.
> > my2c
>
> actually, "ghost" bands do exist.
>
> They do seem to be related to a change in conformation of the plasmid DNA
> under alkaline conditions.
> I remember vaguely an old paper, from the 70s, describing what conformation
> circular DNA can take, and it was defined as "type V" DNA, or something like
> that...
> I might be able to fish it out...
>
> Jose

Jose, Why do you think I should believe to a paper from the 70s?  Do
you know how many crappy papers were published in the past that are
pure BS when we look at retrospect....
my2c



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